Carbureter.



H. H. BUFFUM.

GARBURETER.

APPLICATION HLEDDEC. 11., 1913.

1,202,025, Patented oct.. 24,1916.

2 SHEETS-SHEET l.

n kk) 050% 5 Vw@ W60?,`

333% ozmm mh 720mm H. H. BUFFUM.

CARBURETER.

APPLICATION FILED DEC. II, I9I3.

2 SHEETS-SHEET 2.

Patented Oct. 24,

vw@ wtoz UNITED YSTATES PATENT OFFICE.

HERBERT H. BUFFUM, OF WEIRS, NEW HAMPSHIRE, ASSIGNOR OFiONE-THIRD TO ROBERT M. PIERSON. 0F AKRON, OHIO.

CARBURETER.

ing means adapted to permit the free pas-A sage of mixture through the tube and its connections.

A second object is to furnish means for cordinating the structure and operation of the throttle valve and the tube-actuating devices, such means being preferably of such a nature that the tube may, if desired, be expanded and contracted independently of the throttle movements, thus allowing.the mixture to be enriched above the normal at certain times such as in starting the motor when cold, or to obtain the increased pulling power which results from a slow-burning mixture, or on the other hand to allow the proportion of air to be increased at other times for the sake of fuel economy.

A further object of the invention 1s to" provide the carbureter with a type of throat tube which will allow as near an approximation to the true Venturi tube as is consistent with durability and a desired degree of fluid-tightness of a collapsible tube.

Other incidental objects obtained by my invention will appear from the succeeding description and claims.

Of th'e accompanying drawings, Figure 1 represents a vertical section of a carbureter constructed according to my invention, with the collapsible tube shown in its expanded condition. Fig. 2 represents a similar view with the tube contracted. Fig. 2a represents a cross section of the tube andl its casing, taken above the fuel nozzle. Fig. 3 represents a side elevation of the upper part of the carbureter. Fig. 4 represents a section at right-angles to Fig. 3. Fig. 5 represents a top plan view with the throttle valve partly broken away. Fig. 6 represents a plan view showing a form of footcontrolled Specification of Letters Patent.

Patented Oct. 24, 1916.

Application led'December 11, 1913. Serial No. 805,880.

operating-connections which may be emp loyed. Fig. 7 represents a horizontal sectlon, and Fig. 8 a. side elevation, showing a modified embodiment.

Referring at first to Figs. 1 to 6 inclusive, l0 is a vertical tubular casing having an air-inlet 11 at its ,lower end, spanned by a bridge 12 which supports the fuel jet-nozzle 13, the said bridge and nozzle containing the fuel-duct 14 which leads from an ordinary float-chamber or reservoir 15. In order to obtain the greatest efficiency from the collapsible air-tube which I employ, I prefer to employ a fuel-jet nozzle 13 of considerable relative diameter at its outlet end, and to spread the issuing jet of fuel in an expanded column or sheet of spray and vapor which will fully utilize the increased suction and atomizing effect which I obtain through the employment of such a tube. It will be noted that the jet-outlet 16 is formed in a thin partition 17 and is given an annular form by the conical end or point of a fixed rod 1S supported from below the jetnozzle and occupying the middle of the latter. This particular structure tends to project the issuing fuel in a conical sheet or spray into the passing air current, and the effect is enhanced by means of an external spreader member 19 mounted above the jet orifice and having a conical lower end, this spreader being mounted in a ring 20 connected by bridges 21 with the body of the nozzle and preferably having la threaded connection 22 therewith which permits the spreader to be used as a valve for adjusting the effective. size of the jet outlet. I do not, however, limit myself to this exact construction. One of the important features is to allow considerable expansion or spreading, and some vaporization of the issuing fuel spray before it encounters the air current, and to provide for positively controlling the effective aperture of the air-throat in the aspirator at the mixing point, as by means of the flexible-walled tube herein described. In-other words, there is, as will be evident, an expansion chamber or chambers of considerable capacity interposed between the relatively-small fuel. orifice 16 and the air passage surrounding the final outlet of nozzle 13, the said chamber in this instance being formed between the nozzle wall 17, the spreader 19 and the ring and bridges 20,21.

Such chamber may be made of any suitable depth and capacity, and I nd that its presence results in a marked,- economy in the amount of fuel consumed.

While I am aware that fuel spreaders are not broadly new, it'is to be notedthat the positive control of the air velocity at the mixing point, as attained by my flexiblewalled tube, enables the operator to control at will the pulling power of the aircurrent exerted throughsaid expansion chamber, and to adjust this power to different atmospheric and motor conditions.

23 is the collapsible."air-tube, preferably having a construction similar -to that described in my Patent No. 1,108,128, dated August 25, 1914, being composed of thin longitudinal plates or slots-24 which overlap as shqwnvoin Fig. 2a, their ends being anchored in lower and `upper rings 25, 26. The lower ring abuts against a shoulder 27 near the bottom of the casing 10, and the upper ring is slidable in said casing toward and from the lower ring.

For the purpose of sliding the upper ring 26, I have shown a follower ring 28 mounted to slide in an upper casing or tube-section 29 which is connected with the casing 10 by a screw-threaded coupling or union 30, the said coupling allowing the two parts of the casing to bev separated at a point which aHords convenient access to the interior parts, and also permitting the upper section 29`to be turned at different .angles so as to accommodate its attaching flange 31 to the position of the complemental ange on the engine-pipe, Turning of the follower ring is prevented by a spline connection formed by a pin 32 in the side wall of the casingsection 29, and a longitudinal groove 33 formed in the ring.

The follower ring 28 is provided with a cross-pin 34 on the middle part of which is mounted toturn a roller 35, and this roller 1s engaged by the edge of a cam 36 secured to a rock-shaft 37 which is mounted in bearings in the casing-section29. To the outer end of the rock-shaft is pinned an operating lever or arm 39. Preferably the rock-shaft 37 is, as shown, co-axial with a butterfly throttle-valve 40 which controls the effective size of the mixture-passage, the said valve having two hub-members loosely journaled on shaft 37 on opposite sides of the hub of cam 36, asbest seen in Figs. 4 and 5. The 4cam occupies a diametric slot 41 formed in the throttle valve, which is of such length as to permit movements of the cam independently of the valve, and also provides a certain minimum opening for the passage of the mixture when the throttle valve is completely closed as shown in Fig. 2. To operate the throttle valve I provide an external arm or lever 42 attached tov a sleeve 43 loosely journaled in the casing-section 29 and on the rock-shaft 37, and formed on its inner end with a pair of jaws 44 which embrace between them one edge of the valvedisk 40. 45 is an adjustable stop for either or both of the arms 39, 42.

Fig. 1 represents substantially the normal shape which the tube 23 tends to assume when not under axial compression, its form being then substantially though not quite cylindrical;'that is the plates will be very slightly concaved by the small permanent set which lthey retain after once having been bowed inwardly. On turning the rock-shaft 37 clockwise from the position shown in Fig. 1, the follower ring 28 is, by the action of cam 36 on its roller 35, pushed downwardly, and thereby the ring 26 is depressed and the plates forming the tube 23 are caused to bow inwardly' and produce a contraction or waist in the intermediate portion of the tube surrounding the outlet of the jetnozzle 13. In this way an air-throat of variable diameter is formed around the nozzle.

While the tube 23, as shown in Fig. 2, does not assume the exact shape of the theoretical venturi, it gives a nearer approximation thereto than I believe has heretofore been afforded by any practical form of collapsible tube. The longitudinal collapsing pressure may, as shown, be realized by simple operating connections, and the plates or slats of the tube maybe caused to actas bow-springs which return the tube to its normal diameter when pressure is relieved.

The drawings represent three modes of coordinating the movements of the throttle and tube. The cam 36 and throttle-valve 40 could be caused to move in unison by a rigid connection such as would be afforded by the pin 46 shown in dotted lines in Figs. 4 and 5, and a suitable shape could then be given to 'the edge of the cam to afford at all times'a mixture of substantially constant composition, but since it is desirable at times to vary the richness of the mixture, especially in automobile work, I prefer in that case to provide separate operating connections undercontrol of the driver, and in Fig. 6 have shown the tube arm 39 and the throttle arm 42 4connected by rods 47, 48 to separate pedals 49, 50 which may be separately actuated but are also placed so close together that they may be operated in unison by the drivers foot. The tube army 39 is connected with a spring 51 which is strong enough to force the tube into the position shown in Fig. 2 when foot pressure is relieved. The throttle arm is also provided with a returning-spring 52 and has a fixed collar 53 adapted to abut against a sliding stop 54 whose position maybe adjusted by the operator in the usual way so as to determine the minimum opening of the throttle. Various other forms of controlling mechanism could also be adopted for the purpose of independently adjusting the throttle and tube throughout their respective `ranges of movement, and I do not wholly confine myself to a positive or mechanical actuation of the tube by connections directly under control of the operator. In Figs, 7 and 8 the tube cam and throttle are controlled by the driver through a. single operating device', and act as though rigidly connected through most of their operating'range, but the tube is allowed to be further contracted after the throttle has reached its position of greatest closure. 39 is the controlling arm attached to the outer end of the rock-shaft 37 to which the cam 3G is secured as before, and 4() is the throttlevalve loosely mounted on this shaft as before, but having on the hub of its actuating sleeve 43 an arm 55 between which and a shoulder 56 on the arm 39 is interposed a helical spring 57 which surrounds a curved rod 58, `the latter having one end fixed by a set-screw 59 on the arm 39 and its other end free to slide through an aperture in the arm 55. 60 is a stop on the hub of sleeve 43, normally held against the arm 39 by spring 57. It will be evident that when the throttle-valve 40, moving in a clockwise direction as viewed in Fig.' 8, has been stopped against the walls of the mixture-tube 29 while still retaining a minimum opening for the passage of mixture through the slot 41, the arm 39 may be carried slightly farther in the same direction so as to decrease the size of the waist in the tube 23 and thereby provide a richer mixture for use in starting. At other times, when the throttle-'valve is in a more open position, the spring 57 holds the stop 60 against arm 39 and the tube and throttle are then adjusted in unison,

In practice, especially where the motor speed and load vary widely, as in automobile andto a less extent in motor-boat work, I find that the most satisfactory results are obtained by adjustin the tube independently of the throttle. After once determining the proper size of the fuel-jet orifice and finding that adjustment of the air throat -which gives the best effect for the particular motor and under the existing atmospheric condi-.

tions, I have observed that the throat tube can be left at that adjustment through a very wide range of motor speed. This experienceis contrary to accepted theories' which have led to the development of so-called automatic carbureter-s, which circumstance may be explainable by the fact that heretofore (so far as I am aware) no means has been available for adjusting a properlyshaped Venturi or other aspirator choketube under running conditions to afford exactly theproper air throat for a given size of fuel orifice. The advantage of being able to control the composition of the mixture by plates adapted to form an air-throat of variable 'diameter around said nozzle, a mixture passage beyond said throat, controlled by a throttle-valve, and connections within the control of an operator for actuating said throttle valve land adjusting said tube to vary its throat diameter, said connections adapted' to permit adjustment of the tube ,independently of the throttle-valve.

'2. A carbureter comprising a fuel-jet nozzle, a tube composed of flexible, overlapping, spring plates adapted to be bowed inwardly by axial pressure to form an air-throat of variable diameter around said nozzle, a mixture passage beyond said throat, controlled by a throttle valve, a slidable ring for exerting the axial pressure, a loosely-j ournaled roller supported in said ring, a. transverse rock-shaft crossing said passage and having an external operating member, and a cam vattached to saidV shaft and bearing against the roller.

3. A carbureter comprising a fuel-jet nozzle, a tube composed of flexible, overlapping, spring plates adapted to be bowed inwardly by axial pressure to form an air-throat ot' variable diameter around the nozzle, a tubular casing containing the tube and forming a mixture passage beyond the same, a follower ring disconnected from the tube and slidable longitudinally in said casing. and means for actuating said ring.

4. A carbureter comprising a tubular casing composed of .a fixed anterior section containing a fuel-jet nozzle, a posterior section detachably connected therewith, aA tube mounted in said anterior section and composed of flexible, overlapping, spring plates adapted to be bowed inwardly by axial pressure and end rings in which the ends of saidv 5. A carbureter comprising a tubular casing compo-sed of a fixed anterior section containing a fuel-jet nozzle, a posterior section rotatively adjustable on said xed section and having means for attaching it to an engine pipe, a screw-threaded union connecting the two sections, a flexible-walled tube mounted in said anterior section and adapted to form an air-throat of variable .diameter around said nozzle, and means supported by the posterior section of the casing for operating said tube.

6. A carbureter comprising a fuel-jet nozzle, a tube, composed of flexible, overlapping plates adapted to form an air-throat of variable diameter around said nozzle, a mixture passage beyond said throat, containing a throttle-valve, external arms for operating said tube and 'throttle-valve, and separate connections from said arms, within the operators control, for independently a'djusting said throttle-valve and the diameter of said throat throughout their respective ranges of adjustment..

7. A carbureter comprising a fuel-j et nozzle, a tube composed of flexible, overlapping, spring plates adapted to form an airthroat of vaiable diameter around said nozzle, a mixture passage beyond said throat.l an oscillating throttle-valve located across said passage and having an external opercated in said passage, co-axial with the throttle valve, and having a separate external operating device, for exerting longitudinal pressure on one end of said tube to vary the throat-diameter of the latter.

8. A carbureter comprising a tubular casing containing a fuel-jet nozzle, a tube in said casing composed offiexible, overlapping plates forming an air-throat of variable diameter around said nozzle, a mixture passage in the casing beyond said throat, a rock-shaft mounted across said passage and having an external operating arm, a butterfly throttle-valve loosely surrounding said shaft and formed with a slot, said valve having a sleeve surrounding the shaft and provided with an external operating member, and a cam attached to the shaft and occupying said slot, for exerting longitudinal pressure on one end of said tube.

9. A carbureter comprising a fuel-jet nozzle having a relatively-thin end wall formed with a discharge orifice, and a relativelylarge outside diameter at its discharge end` means for causing the fuel to issue from said nozzle substantially in the form of a conical spray or film, a tube composed of flexible overlapping plates adapted to form an airthroat of variable diameter around the discharge end of said nozzle, and means foractuating said tube to vary its throat aperture.

10. A carbureter comprising an aspirator having a variable air-throat formed by relatively-adjustable members, means for positively controlling the size of said throat at the will of the operator, a jet-nozzle having a relatively-small fuel orifice, and a relatively-large chamber interposed between said orifice and air-throat for permitting free expansion and vaporization of the issuing fuel spray before it encounters the air current.

11. A carbureter comprising a jet-nozzle and a surrounding air-tube forming an aspirator, said tube composed of flexible, overlapping, spring plates adapted to be more or less bowed inwardly to vary the size of the air-throat, said ynozzle having a relatively-small fuel orifice and a final outlet to the aspirator of relatively-large diameter permitting the free expansion of the fuel before it encounters the air-current, and devices for throttling the mixture and for adjusting said` tube to control the size of the air-throat. atlng device, and an oscillatmg member lo- .12. A carbureter comprising a fuel-jet nozzle, a flexible-walled tube adapted to form an air throat of variable aperture around -the outlet of said nozzle, a throttle valve interconnected with one end of said tube, and means connected With said end of the tube for adjusting the latter independently of the throttle valve.

13. In a carbureter, the combination of aAfuel-jet nozzle, a flexible-Walledtube forming anair throat of variable aperture about the outlet end of said nozzle, a throttle valve in the mixture passage leading from lsaid tube, operating connections between said throttle-valve and the posterior end of the tube, and means for axially adjusting said tube by its posterior end independently of the throttle-valve.

14. In a carbureter, the combination of a mixture passage containing a throttle-valve mounted on a rock-shaft, a cam within said passage co-axial with said shaft, a fuel-jet nozzle, and a tube of variable aperture surrounding the same and composed of flexible overlapping spring blades, said tube being` axially adjustable by the action of the cam.

In testimony whereof I have hereunto set my hand in the presence of two subscribing Witnesses, this'Sth day of December, 1913.

HERBERT I-I. BUFFUM.

Witnesses:

C. J. HAYroRD, ERWIN SANBORN. 

